{
  "name": "Crossref",
  "slug": "crossref",
  "category": "Data & Reference",
  "description": "Metadata for 140M+ DOIs — papers, books and citations, free in the polite pool.",
  "status": "live",
  "healthScore": 90,
  "grade": "A",
  "auth": "none",
  "cors": "yes",
  "limits": "Free, add mailto for polite pool",
  "docs": "https://www.crossref.org/documentation/retrieve-metadata/rest-api/",
  "sampleEndpoint": "https://api.crossref.org/works/10.1038/nphys1170",
  "lastChecked": "23 Oct 2026",
  "firstSeen": "2026-10-22",
  "uptime": {
    "endpointChecks": 2,
    "liveChecks": 2,
    "pct": 100
  },
  "checks": [
    {
      "d": "2026-10-22",
      "s": "live"
    },
    {
      "d": "2026-10-23",
      "s": "live"
    }
  ],
  "urls": {
    "page": "https://freeapis.akclnt.com/api/crossref/",
    "history": "https://freeapis.akclnt.com/api/crossref/history/",
    "badge": "https://freeapis.akclnt.com/badge/crossref.svg",
    "statusJson": "https://freeapis.akclnt.com/api/crossref.json",
    "watchFeed": "https://freeapis.akclnt.com/watch/crossref.xml"
  }
}